Brake Bleeding

Hey, Kevin Bass here at Vintage Bike Addiction. I'm here today with Fix My Hog, doing a little Dennis Kirk maintenance on a bike here. Today, what we're gonna talk about is how and when you should bleed your brakes and check your brake pads on your motorcycle. Now, obviously, when you start to ride and you put on a lot of miles, you want to remember there are a lot of little things that you want to be keeping up on. You don't want to wait till it's worn out and wrecking stuff to fix it.

And brakes are very important because obviously that's your stopping power that's gonna keep you safe. So, always, always, always, um, look at your manufacturer's manual for your motorcycle. Uh, they're all specific depending on years and makes and models and whatnot. So look through your manual, see what they recommend. For this bike here, uh, and probably most bikes in the earlier ages here, the newer ones, um, you want to check your brake pads and your fluid after your first 1000 miles, your initial kind of break-in period of riding it.

And after that first 1000 miles, you know, you check your fluid, make sure everything's good, check your brake pad where, typically, it's probably gonna be OK. After that, you want to check it every 5000 miles, sooner if, if you can, but, uh, maximum, you'd want to wait about 5000 miles per check. And then what you're gonna be looking at is how much, uh, wear is on your brake pads. You want to inspect your rotors. Are there any gouging, scoring?

Does it look like there's any major issues, any warpage that could be going on there? Check all your lines and just check your fluid and check your, tension. Now, on this bike, the front, uh, brake lever right now is really, really soft and kind of squishy. So that tells me a few things. One, it could be that the brake pads are worn out.

Two, it could be there's water or moisture, some air in the line, and the lines are making it more squishy. Now, to check your brake pads, um, I did get some new ones from Dennis Kirk here just to kind of check and see what the new ones would look like. So we have some brand new pads that we, uh, got from Dennis Kirk, and we got them just to make sure. We checked the thickness on these and what brand new ones were. And then we went down below to check your pads here, you want to check the thickness of your pads behind the rotor so you can take your straight edge.

Have a light on, get in there and just measure how much pad life is there. Now, mine's well within spec. These are very, very nice thick pads yet, so I'm not gonna replace those at this time. I'm just gonna worry about bleeding the brakes. Same thing goes for the rear.

We checked the rears. They're both in spec, um, rear brake pedal here in the master. On here, same process for bleeding the brakes with the front and rear. The only difference is you got a foot pedal here, you got a hand control there. So the rear brakes were in spec.

We got a good pedal here. We're not gonna deal with that. The front brake pads are good, so we're not going to replace the pads, but we are gonna go through and just bleed them and see if we can get this to tighten up a little bit. Now, we always use 5 in these or whatever your manufacturer calls for for your bike, but this one does call for 5. We use Spectro oils for all of our stuff, Spectro 5 brake fluid.

They're a great company, make a great product, and it's stuff that you can, you can trust and use without worrying about any issues. So we're gonna go ahead now. Uh, we're gonna get this master cylinder cover off. We're gonna lower the bike down a little bit. Um, when you do bleed your brakes, you do wanna have some sort of a catch basin for your fluids, OK?

Because what's gonna happen is when we pump this up, I'm gonna crack the bleeder screw here. A lot of pressure's gonna be in there. If you don't have a hose on here, all that brake fluid is gonna squirt all over your engine, all over your motorcycle, and make a big mess. You don't want that. So what you want to do is kind of come up with what we did here.

We got a bucket with a hose taped to it, so I'll be able to pull that protective cap off my bleeder screw. I'll be able to put the tube right on the end of my bleeder. And now, when I pump this up, I'll have this on a box, and I pump it up and I crack my bleeder, that fluid will go down the tube into the bucket and not make a big mess. OK? So good pro tip there.

You don't want that all over your engine; it's gonna make a huge mess. So we're gonna get this bike lowered down a little bit, hook up all this, get ready to go through and show you how to bleed the brakes. All right. Now that we've checked their caliper pads and the calipers, everything looked good. Um, we're gonna get in there actually just bleeding the brakes.

So we're gonna do this front, uh, section here. This bike has kind of a chrome decorative trim kit, so I had to use a little Allen wrench to loosen those screws. That chrome cover plate can just get lifted up and over and off to the side out of the way. Then you're gonna want to release the screws in your master cylinder cover. Now, there is a rubber boot.

Attached to the cover that does expand and contract with the brake fluid. So make sure you got all that together. Keep it clean, keep it out of the dirt and debris. You don't want any garbage getting in your master cylinder and down into those lines which will cause the brakes to act funny. So to bleed these brakes, I'm gonna leave this loose for right now.

Just set it on there because sometimes as you're bleeding them, this will bubble up and spit. You don't want that squirting all over your motorcycle. Now, we're gonna pump up the brakes here. And then we're gonna crack the bleeder valve, which you can see right here, and that's gonna let the pressure of the line in the calipers compress, and it's gonna squirt fluid. Now as we talked about earlier, you don't want to have that squirting all over your bike.

Now the manual does say get your bike to level when you do this. Now my bars were at a different angle, so I kinda, we stood it on a lift and I turned my bars just right to try to get this at a nice decent level angle. So we're gonna move our fluid bucket. Put our hose on our bleeder there, OK. Uh, it should be a 3/8 on that bleeder; crack it, which it is.

Now what you want to do is just start pulling it in nice and slow and easy. Pull it as tight as you can, then let it release. Pull it in tight as you can, let it release. Sometimes I'll even do a couple of little quick short ones, some long ones just to try to build pressure the best I can. Now I'm gonna hold it all the way in.

Don't let that off as I crack the bleeder. OK, I'm gonna crack it briefly and then tighten it back up. When I cracked the bleeder, that lever came all the way down to the, to the grip. I lost all pressure there, and that's what you want to see; you want to see the fluid starting to get pushed through. I do see a couple of bubbles in there, which tells me the reason why this may have been soft is because we know the pads were still good.

It was a soft lever. We may have some air bubbles in our line. So now we'll do the same thing; pump it up. And then we'll crack the line again. Turn it back in tight, and you never wanna let go of this lever until you have your bleeder tight again.

If you do, you're gonna suck air in the line, OK? Now, I did that twice. I'm gonna check my fluid. Fluid level is still plenty good right now. With the cover off, I'm gonna slowly pull on it and I can see the fluid bubbling back up, so I know we're getting pressure build-up there.

I'm gonna do this a few times because I'm gonna try to purge this system. So basically what I'm gonna do is bleed it until my fluid level gets pretty low so I can put fresh fluid in and then chase that. So we're kind of flushing the system while we do this. So again, I'm gonna start pumping it up. Hold it, crack it, and tighten.

And you do wanna, when you pull it in, let it, uh, go back to normal and give it a second to kind of build up, then pull it in again. Hold it. See, the fluid is starting to work its way down now into our bucket. And I am noticing the lever is getting a little more stiff and firmer than it did before we started this, so it is getting rid of maybe possibly a little bit of air that was in the system. Check our fluid again.

We're getting about halfway down. Probably do it two more times, then I'll add some fluid. And then we'll go to the other side. Definitely getting a better, stiffer front brake. It's pulling there now, so it's definitely doing something.

So that's why it's good to check this. You know, the first 1000 miles and every 5000 miles, check your pads, check your fluid. If you feel a squishy pedal or a lever, you want to bleed the brakes like we're showing here. OK, so we've purged this side. I don't see any more air bubbles.

I'm getting good, solid, clean fluid coming out of there. So I'm going to top this off with some 5 spectral, and the book says you want to be about an eighth of an inch from the top of your reservoir. So if I look at this, I see my eighth inch. There's not much room there. Eighth inch is going to be about there, so I'm going to carefully put my 5 in.

Check with my ruler. It's about a quarter inch. And here we are. OK. So now, I'm going to set this cover back on like we've been doing.

And all we have to do for the other side is the exact same process. We're just going to hook the hose up to the bleeder on that side. We'll do the pump and then we'll crack the bleeder, let it bleed through, and once we get that side done, hopefully then this lever will be back to where it should be, a nice firm lever. We'll top off our fluid, make sure it's at the correct level, and we'll button this thing up and be ready for the road. All right, so we've been through the system.

We checked the front and rear brake pads. Again, remember to check those your first 1000 miles and every 5000 miles after that. Um, same with the brake fluid; now we went through, checked the brake fluid. We use good high quality 5, and it does say in the master cylinder as well. It requires 5.

Spectral is what we use. Got this through Dennis Kirk. They ship today. So if you ever need anything for your maintenance, go to Denniskirk.com, put it in your cart, hit buy now, and it'll be shipping that same day. So again, just to recap, uh, we checked the front and rear pads.

They had over a 0.04 thickness of pad left, so they're still within spec. If they get down to 0.04 or less, you want to replace those. Both those checked out, um, rear brakes were fine. We checked the fluid. It was good and didn't need to be bled.

Front one was really squishy, so we went through and did the left side, uh, pumped up the brake. Held it, cracked the bleeder, let it bubble out. There was some air in that line. We did the other side the same way, found some air in that. Now I have a good, firm front brake lever.

It's not so squishy. I can't pull all the way to the grip. So now I know my front brakes are working well. We topped off our fluid or 5 to 1/8 inch below the master cylinder top. And we capped it back up, buttoned it up, and cleaned up our mess, made sure there's no fluid on the brake rotors or anything else that could get slippery and cause you not to be able to stop.

But at this point, I trust now our brakes are good. We'll be ready to go, and I'll be checking them again in about 5000 miles. So again, DennisKirk.com for anything you need, Spectro oils for your fluids, and you'll be good to go.